Distribution of Enhalus acoroides According to Waves and Currents

Author(s):  
Kota Nakase ◽  
Tomokazu Murakami ◽  
Hiroyoshi Kohno ◽  
Akiyuki Ukai ◽  
Akira Mizutani ◽  
...  
Author(s):  
Nobuhiro Matsunaga ◽  
Misao Hashida ◽  
Hiroshi Kawakami

2017 ◽  
Vol 11 (3) ◽  
pp. 249
Author(s):  
Lisa Fajar Indriana ◽  
Yuli Afrianti ◽  
Sitti Hilyana ◽  
Muhammad Firdaus Firdaus

Teripang pasir, Holothuria scabra merupakan komoditas hasil laut yang bernilai ekonomis tinggi. Penangkapan berlebihan stok di alam mendorong berkembangnya kegiatan budidaya. Penempelan merupakan fase kritis pada larva teripang karena terjadi peralihan sifat planktonis ke bentik yang memerlukan substrat. Penelitian ini bertujuan untuk mengetahui preferensi penempelan, pertumbuhan, dan sintasan larva H. scabra fase penempelan pada substrat lamun yang berbeda. Penelitian menggunakan metode rancangan acak lengkap dengan perlakuan empat jenis daun lamun berbeda dan lima ulangan. Perlakuan terdiri atas Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), dan Cymodocea rotundata (L-4). Jumlah awal larva sebanyak 1.000 individu dan substrat dirangkai dengan luasan yang sama sebesar 12 cm x 17 cm untuk setiap unit penelitian. Hasil penelitian menunjukkan jenis lamun yang digunakan sebagai substrat berpengaruh secara nyata terhadap preferensi penempelan dan sintasan larva teripang pasir, namun tidak berpengaruh terhadap pertumbuhan. E. acoroides menunjukkan hasil terbaik dengan preferensi penempelan 0,26 ind. cm-2 dan sintasan 10,66%; sehingga layak digunakan sebagai substrat penempelan dalam pembenihan teripang pasir, H. scabra.Holothuria scabra larvae on different seagrass substrates. By: Lisa Fajar Indriana, Yuli Afrianti, Sitti Hilyana, and Muhammad FirdausSandfish Holothuria scabra is marine commodities with a high economic value. Overfishing of natural stocks has compelled an interest to begin aquaculture practice. Settlement is a critical phase for the planktonic larvae as they will transform to benthic form in the presence of substrate. This study aims to evaluate the settlement preferences, growth, and survival rate of H. scabra larvae settled on different seagrass leaves. The research was conducted using the Completely randomized design with four different species of seagrass leaves and five replications. The treatments consist of Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), and Cymodocea rotundata (L-4). Initial number of larvae was 1,000 individuals and the substrate was set with same widthof 12 cm x 17 cm for each unit. Results of the experiment indicated that settlement preference and survival rate of H. scabra larvae was significantly affected by seagrass used as substrate while no significantly differences was observed for growth of larvae. E. acoroides showed the best result with 0.26 ind. cm-2 settelement preference and 10.66% survival rate, so that suitable to be used as settlement substrate in H. scabra hatchery.


Author(s):  
Tatiana Shulga ◽  
Tatiana Shulga ◽  
Leonid Cherkesov ◽  
Leonid Cherkesov

In this work, the waves and currents generated by prognostic wind in the Sea of Azov are investigated using a three-dimensional nonlinear sigma-coordinate model. The mathematical model was also used for studying the transformation of passive admixture in the Sea of Azov, caused by the spatiotemporal variations in the fields of wind and atmospheric pressure, obtained from the prediction SKIRON model. Comparison of the results of numerical calculations and the data of field observations, obtained during the action of the wind on a number of hydrological stations was carried out. The evolutions of storm surges, velocities of currents and the characteristics of the pollution region at different levels of intensity of prognostic wind and stationary currents were found. The results of a comprehensive study allow reliably estimate modern ecological condition of offshore zones, develop predictive models of catastrophic water events and make science-based solutions to minimize the possible damage.


Author(s):  
AbdAlla M. AbdAlla ◽  
AbdAlla M. AbdAlla ◽  
Abkar A. Iraqi ◽  
Abkar A. Iraqi ◽  
Magdy M. Farag ◽  
...  

Sea level and wave data at Salalah coast (Oman) were used to simulate nearshore waves and current during the tropical cyclone ARB01 (9 May2002). STWAVE model (Steady State Spectral Wave) was applied for nearshore wave simulation, while M2D model ((Two-Dimensional Depth Averaged circulation model) was used to simulate nearshore current. The results of simulations (taking into account the mutual effects of both current and waves) showed that: The significant wave heights generally decrease from about 6m at the domain boundary to about 1 m close to the coast. The wave heights during the ebb period were higher than that during the flood period by about 1.5m. Along Salalah coast, higher waves were found along the eastern side of the domain. This is because the shielding effect of breakwater, which protect the western part of the coast from high waves. Relatively Strong current with values up to 1.5 ms-1 were found in the nearshore region during both ebb and flood periods. The M2D model results also showed cyclonic circulations during these periods which help in the renewal of harbor waters. Generally, the model results showed good agreements with observations in the investigated area.


Sign in / Sign up

Export Citation Format

Share Document